Safety car step



Mar. 20, 1 923. 1,449,031

F. D. BLAKE SAFETY CAR STEP Filed Dec. 14, 1920 3 sheets-sheet l Mar. 20, 1923.

F. D. BLAKE SAFETY CA/R STEP Filed Dec. 14, 1920 5 sheets-sheet 5 Patented Mar. 20, 1923.

ii l S it it? it:

FEED D. BLAKE, OF CHARLOTTE, NORTH CAROLINA, ASSIGNOR TO AUTOMATIC SAFETY CAR STEP COMPANY, DELAWARE.

Oi ACELAlV'Iit, GEORGIA, A CORPORATION OF SAFETY CAB, STEP.

Application filed December 1a, 1826.

To all iii/com it may concern:

Be it known that I, Finn) D, BLAKE, a citizen of the United States, residing at Charlotte, in the county of liflechlenlmrgand State of North Carolina, have invented a new and useful Improvement in Safety Car Steps, of which the following is a specification.

The object of the invention is to provide a step of the folding or extension type adapted for use in connection with railway and street cars and similar vehicles as a means of dispensing with the separate box or block for facilitating the alighting from an d boarding of such conveyances, which can be extended only when the vehicle has reached a fullistop and. which will be released for folding movement, automatically by progress in either direction thereof; to

provide a step which is exposed to a constant yielding force or counterbalancing influence tending to fold the same under such conditions that while such tendency is positive, promptly responsive when the step is released, and effective to normally retain the same in a retracted and inconspicuous relation to the platform or permanent steps, it is successfully opposed by a relative light weight, as of a person standing or resting a foot on the step as in preparing to mount or in leaving the same, to guard against the possibility of accident due to a forcible or abrupt closing movement; to provide a step of which the folding movement at its incep tion is substantially parallel with the plane of its bearing or supporting surface, and wherein the tension or efficiency of the folding force or tendency is reduced as the step approaches its extended or operative position and is increased as it approaches its folded or normal position to the end, for instance, that vibration or rattling due to the movement of the vehicle is minimized; to provide a step which isactuable to open or extended position and is so held solely by fluid, preferably pneumatic, pressure, to the exclusion of latches, locks, trips and like auxiliary agencies subject to wear, disai: rangement or displacement by vibration and disqualification for proper functioning by accumulations of dust, ice and snow; and to provide means whereby the manipulation necessary to cause the extension or the folding of the step may be accomplished from either the platform or the side of the car.

Serial No. 430,669.

Further objects and advantages of the invention will appear in the course of the de scription of a preferred embodiment of the essential elements and functional factors thereof, it being understood that changes in form, proportions, arrangement and like details may be resorted to within the scope of the appended claims without departing from the principles involved.

In the drawings Figure l is a View of the apparatus applied to a car as seen in a side elevation of the latter.

Fig. 2 is a sectional view of the same taken on a plane through the ordinary or permanent steps parallel with the direction of travel thereover.

Fig. 3 is a rear or inside elevation partly in section throughthe car platform on a plane at right angles to thatof Fig. 2.

Figs. 4: and 5 are detail sectional views of the trip mechanism for releasing the folding step for retraction upon the movement of the step-carrying vehicle.

Fig. 6 is a detail section of the step 0p era-ting element.

Fig. 7 is a similar viewof the controlling valve.

Fig. 8 is a similar View of the trip.

Fig. 9 is a perspective View of the apparatus detached.

The operating mechanism. which is de signed for use in connection with a counterbalanced step 10, supported by hangers 11 and connected with a rock shaft 12 having in this instance the weight 13 which serves as the counterbalancing element to yieldingly retract or withdrawthe step from the extended operativeposition shown in full lines to the folded position shown in dotted lines in Fig. 2, consists essentially of a fluid pressure feed line 14 connected with a suitable source such as the reservoir 15 and communicating with fluid actuated operating device 16 having a cylinder 17 and piston 18, of which the stem 19 is connected to a crank arm 20 on the rock-shaft 12, the feed line being intersected by a controlling valve 21, manually actuable by reversible setting means indicated at 22. The invention also contemplates automatic safety trip mechanism 23 including a pressure relief valve for reducing the step setting pressure in the feed line to release the step for folding movement when the vehicle starts and lll) prevent the application of step setting pressure to the actuating plunger of the operating device while the vehicle is in motion.

The controlling valve which is normally closed, as shown in Fig. 7, serves to admit pressure from the source when a rocker 24, having an arm connected with the stem 26 of the plunger 27, is actuated by depressing the pedal 28 or hand lever 29, and the return of the valve to closed position may be accomplished by means of the pedal 80 or by reversing the movement of the hand lever.

4 The valve plunger is yieldin ggly held seated h pressurefrom the feed line.

extended.

in position to close the supply port 31 by a, spring 32, or equivalent yielding forte which is less than that required to actuate the plunger 1.8 of the step operating device so that when the valve plunger is unseated to ex 3086 the supply port, it is so held by the feed ine pressure. The valve casing 33 is provided with an outlet port 34 to the feed line and a bypass 35 connecting an exhaust port 36 with the feed line,vents 3'? being formed in the valve casing for the escape of The exhaust port 86 is closed by the valve when held unseated by feed line pressure, and the face of the valve plunger is inaccessible to supply pressure when the valve is seated.

The cylinder and plunger of the step-op erating device serve as a dash-pot to insure a gradual folding movement of the step when the feed line pressure is reduced to release the step for return by the counterbalancingelement consisting of weight 13, but in order to insure the slowness and gentleness of this movement at its inception or start so that it may effectually be resisted by even a slight weight on the step, such as might'be imposed by the foot of a person about to ascend or just leaving the same at the moment of release, the counterbalancing element is arranged toexert a graduated influence on the step as by disposing it when the step is extended in a position near the vertical plane of the axis of its orbital move ment. Thus it exerts its maximum step moving influence when thestep is folded and its minimum influence when the step is The function of the pressure relief valve is to reduce the step setting or extending pressure in the feed line automatically upon the movement of the step-carrying vehicle whereas in accordance with the foregoing description the controlling valve is designed to provide for the manual or voluntary reduction of pressure for the same purpose, and to this end the casing 38 is connected with the feed line 14 by a branch 39 and is provided with an exhaust port 40 controlled by the plunger 41 normally held seated or in port-closing position by a constant yielding pressure represented by the spring 42 which is opposed to feed-line pressure (which obviously is variable) and of which the tension or resistance is less than the resistance offered by the step extending means (due to the constant force of the counterbalance 13) and which must be overcome by feed-line pressure in order to extend the step. In other words, with the relief valve seated the increase of feed line pressure will first overcome the constant resistance odered to the unseating of the relief valve by the spring 42 before it will be sufficient to extend the step, and in order to permit of an increase of feed-line pressure adequate to set the step it is necessary to prevent the unseating of the relief valve sufficiently to expose the exhaust port 40 to permit a reduction of feed-line pressure. This is accomplished by stop mechanism which is operative only under prescribed conditions as when the vehicle is stationary or has come to a full stop, and consists of a trip 43 pivot-ally suspended fro-m the stem 44 of the relief valve and having located in the path of unseating movement of the relief valve an obstacle movable relatively to said path of the valve when the vehicle moves and in a direction which is transverse or in intersectingrrelation to said path, such as a car wheel axle indicated at 45. By this means, the first action on opening the supply or controlling valve to charge the feed line from the'source of pressure is to overcome the constant resistance 42 and the unseating movement of the relief valve is checked by the stop mechanism to prevent exhaust at the port 40 if the vehicle is stationary, whereupon further pressure in the feed-line will set the step for use. If the stop or obstacle represented by the axle 45 is moving, even very slowly or slightly, the arcuate surface of the sector-shaped trip'rolling' thereon will release the valve 41 and permit the reduction of feed line pressure through the port'40, (see Fig. 5).

From an extended or operative position the folding movement of the step is first horizontal, owing to the pendent position of tile hanger 11 and the relation of the'curved step arms 46 and crank arms 47 on the rock shaft 12 is such as to fold the movable step close to and parallel with the lowermost of the permanent steps 48with all connected parts above the plane thereof. so as to be" out of reach of obstacles on the road-bed.

I claim:

1.. An extension car-stop operating mechanism having fluid pressure actuated step extending and holding means opposed by a yielding step folding resistance,and pressure reducing means for the actuating pressure, releasable by movement of the step carrying vehicle and including an element exposed to step actuating pressure and exerting an opposing yielding resistance thereto.

2. An extension car-step operating mechanism having fluid pressure actuated step extending and holding means opposed by a yielding step folding resistance and pres sure reducing means for the actuating pressurereleasable by movement of the step carrying vehicle and including an element exposed to step actuating pressure and exerting an opposing yielding resistance of less tension than the step-folding resistance.

3. An extension, car-step operating mechanism having fluid pressure actuated step extending means opposed by a yielding step folding resistance pressure relieving means having an exhaust controlling plunger exposed to the step-extending pressure and a trip actuable by movement of the step car rying vehicle for temporarily limiting the pressure controlled movement of said plunger.

4. An extension car-step operating mechanism having fluid pressure actuated step extending means opposed by a yielding step folding resistance pressure relieving means having an exhaust controlling plunger exposed to the step-extending pressure and provided with a yielding pressure opposing element of less tension than the step-folding resistance.

5. An extension step operating mechanism having constant yielding step folding means of graduated tension, and a step extending agency variable in tension With relation to and throughout a range exceeding that of the folding means.

6. An extension step operating mechanism having a constant yielding step folding tendency of a tension which is reduced as the step approaches its operative position, and an opposed yielding step extending agency variable in tension throughout a range exceeding that of the step folding tendency.

7 An extension step operating mechanism having yielding step folding means exerting a constant influence, and step extending means actuable by a variable fluid pressure. and pressure varying means controlled by the movement of the step carrying vehicle.

8. An extension step operating mechanism having yielding step folding means exerting a constant influence, a step extending means actuable by a variable fluidpressure, and pressure reducing means controlled by the movement of the step carrying vehicle.

9. An extension step operating mechanism having yielding step folding means, yielding step extending means actuable by variable fluid pressure, pressure reducing devices normally held inactive by a constant pressure exceeded by that of the step folding means, and actuable by step extending pressure, and means for supplementing said constant pressure when the vehicle is at rest.

ll). A normally folded and counter-bal anced extension car step, pneumatically actuable means for extending the step and retaining it in operative position, and means for relieving the pneumatic actuating pressure, consisting of a cylinder having an ex.- haust port, a piston valve exposed to the said actuating pressure, and a pivotal pendant trip disposed radially in coincidence with the path of said piston valve.

.11. A normally folded and counterbalanced extension car step, pneumatically actuable means for extending the step and retaining it in operative position, and means for relieving the pneumatic actuating pressure consisting of a piston exposed to said actuating pressure and movable thereby to open an exhaust, and a pivotal pendant strip axially movable with and by said piston and adapted for peripheral contactwith acar axle for limiting the pressure actuated movement of the piston.

12. A normally folded and counter-balanced car-step, pneumatically actuable means for extending the step and retaining it in its operative position, a source of pressure supply and a controlling valve for admitting pressure from the source to the step extending means, andconsisting of a cylinder and a yieldingly actuated piston, the cylinder having a supply port for normal closure by the piston and also having connected feed and exhaust ports of which the latter is closed when the piston is retracted 'to expose the supply port.

18. A normally folded and counter-balanced carstep, pneumatically actuable means for extending the step and retaining it in its operative position, a source of pres sure supply and a controlling valve for admitting pressure from the source to the step extending means, and having a piston which is movable to cut off position by a constant pressure less than the step actuating pressure and is exposed to the latter when moved to open position.

14. An automatically foldable extension car step having pneumatically actuable extending and holding means, and a controlling valve for admitting pneumatic pressure to said means, and including a. diaphragmatic element movable in opposite directions to admit and cut off said pressure, and exposed in opposed relations to constant and variable pressures of which the latter is represented by the pneumatic step actuating pressure when said diaphragmatic element is in position to admit pressure.

15. An automatically foldable extension car step having pneumatically actuable extending and holding means, and a controlling valve for admitting pneumatic pressure to said means, and including a piston movable in opposite directions. to open and closed positions, respectively by variable and constant pressures of which the latter is less than the step actuating pressure, said piston being exposed to the latter when in open position.

16. An automatically foldable extension car step having pneumatically actuable extending and holding means, and a controlling valve for admitting pneumatic pressure to said means, and including'a piston exposed to step actuating pressure when in valve opening position and exposed in the opposite direction to a constant pressure which is less than step actuating pressure.

17. An automatically foldable extension car step having pneumatically actuable extending and holding means, and a control ling valve for admitting pneumatic pressure to said means, and including a piston movable to valve open and valve closed posi tions, and being exposed in opposite directions respectively to variable and constant pressures.

18. An automatically foldable extension car step having pneumatically actuable extending and holding means, and a controlling valve for admitting pneumatic pressure to said means, and including a piston exposed to step actuating pressure When the valve is open and exposed in the opposite direction to a constant pressure less than step actuating pressure.

19. An automatically foldable extension car step having pneumatically actuable ex tending and holding means, and a controlling valve for admitting pneumatic pressure to said means, and including a piston exposed to step actuating pressure when the valve is open and exposed in the opposite direction to a constant pressure. less than step actuating pressure, and means actuable by movement of the step carrying vehicle for reducing the step actuating pressure.

FRED D. BLAKE. 

